There have also been cases of hearing loss reported in patients using Revatio, according to the FDA.

In most of the cases, the hearing loss involved one ear. The hearing loss was either a partial or complete loss of usual hearing.

In about one-third of the reported cases, hearing loss was temporary. In the rest of the cases, hearing loss was ongoing at the time of the report or the final outcome wasn't described in the report.

Viagra, Levitra, and Cialis haven't been proven to cause hearing loss, but the alert was warranted due to "the strong relationship between the use of these drugs and sudden hearing loss in these cases," states the FDA.